Automotive primer sealer.

Anyone have some recommendations?

Preferably something reasonably priced because I'm going to need a lot of it.

I used the TCP global stuff on my BMW when I repainted it. The 2k urethane stuff works great, is pretty cheap and lays down nice with a Harbor Freight gun. Here's what I used on my BMW. http://www.tcpglobal.com/KUS-KIT-KUP405-GL_2.html?sc=115&category=1931628

These are pics of the primer after a quick 1000 grit wet sand.

And here it is with the single stage urethane applied over, wet sanded and buffed.

i got the bare metal etching primer from paintforcars.com for the chevelle and i mixed a little bit for the datsun to hit the bare spots and it worked very nice. it was $92 for 2 gallons

I use the cheap Nason 2k stuff from the local auto paint supply place. But if I'm putting base/clear over it I use a dedicated sealer. With a single stage urethane like Fulthane I wet sand the primer w/ 600 and shoot a tack coat plus 3 wet and it looks really good.

Southern Polyurethane

Never used it but have heard good things.

Best idea is find a automotive paint supplier in your city. Tell them what you need and normally they can get you the most reasonable product that will work. Bonus since your going to need quite a bit of it they sometimes will cut you a deal since your buying more than a gallon.